Oil burner



Oct. 21, 1941.

H. F. T APP ETAL OIL BURNER Filed Jan. 27, 1940 5 Sheets-Sheet 1 INVENTOR HARRY/F721 41v v 4:01.74 Z'JPEAR BY 50 ORN s Oct. 21, 1941. 'T r 2,259,535

v OIL BURNER Filed Jan. 27, 1940 5 Sheets-Sheet LEOLY/V SPEAK BY H. F. TAPP ETAL Oct. 21, 1941.

OIL BURNER Filed Jan. 2'7, 1940 5 Sheets-Sheet 3 [NVENTOR HARRYETAPP AND LEOLY/V EJPEAR Oct. 21, 1941. PP r 2,259,535

OIL BURNER Fild Jan. 27, 1940 5 Sheets-Sheet 4 IN ENTOR HARRY 721? mm BY 801,74 EJPJAR Oct. 21, 1941. H. F. TAPP ETAL 2,259,535

OIL BURNER Filed Jan. 27, 1940 5 Sheets-Sheet 5 mTORN zs Patented Oct. 21, 1941 UNITED STATES PATENT OFFICE OIL BURNER Harry F. Tapp, Longmeadow, and, Leolyn F. Spear, Westfield, Mass., assignors to Gilbert & Barker Manufacturing Company, West Springfield, Mass., a corporation of Massachusetts Application January 27, 1940, Serial No. 315,940

Claims. (01. 158-36) This invention relates to improvements in oil burners and, more particularly, to improvements which enable satisfactory operation with the use of relatively heavy and viscous fuel oils.

The invention has for its general object the provision in an oil burner ofmeans for preheating the oil and for bringing all oil within the burner structure up to a selected predetermined temperature in as short a time as possible and before flow of any oil from the nozzle is permitted.

The invention has for a particular object the provision of two oil-heating means, one of which is associated with the boiler, or-other heating unit, and dependent for its efiectiveness on operation of that unit and the other of which is operable independently of the unit and can be brought into effective operation coincidentally with the starting up of the motor-driven pump of the burner, together with a means for initially circulating a relatively small body of oil in a relatively short path which includes the second and excludes the first heating means. The oil thus circulated heats the necessary parts of the burner structure, particularly the oil supply passages to the nozzle and the nozzle itself, and a quick raising of the temperature can be effected. After the initial heating of the oil in this manner, oil is permitted to flow to the nozzle for ignition and the oil used for heating purposes is caused to circulate in a longer path which includes the first heating means.

The invention also has for an object to provide in a burner of the type described, a valve which is responsive to oil temperature and which controls the flow of oil into the feed conduit of the oil-atomizing nozzle and opens only when such oil has been raised to the desired predetermined temperature, together with a circulatory oilheating system including jackets or other passages which extend along opposite sides of said conduit from end to end thereof, whereby all the oil that is trapped between the valve and nozzle may be effectively heated. Another object of the invention is to provide in a burner of the type described, a manifold in which are grouped all the necessary valves, thermostats, or other instruments necessary to the accomplishment of the objects above set forth and ,in which are formed inlet and outlet chambers for the low-pressure oil used for heating purposes, and a valve chamber for the high-pressure oil to be fed to the feed conduit of the oil nozzle.

an adapter ring which is arranged to be inserted between the fan housing and the air tube of an oil burner and which carries the aforesaid manifold, the arrangement enabling an ordinary burner to be converted easily and conveniently into one having the oil-preheating provisions desirable to render the burner capable of handling heavy fuel oils.

These and other objects will best be understood as the detailed description proceeds and they will be pointed out in the appended claims.

The invention will be disclosed with reference to the accompanying drawings, in which:

Figs. 1 and 2 are small-scale, top-plan and side elevational views, respectively, of a burner embodying the invention;

Fig. 3 is a fragmentary cross sectional view, taken on the line 33 of Fig. 1 and drawn to a larger scale;

Figs. 4 and 5 are sectional plan'views taken on the lines 4-4 and 5-5, respectively, of Fig. 3;

Fig. 6 is a sectional elevational view, taken on the line 6--6 of Fig.1 and drawn to a larger scale; I

Figs. 7, 8 and 9 are sectional views taken on the lines 1-4, 8-8, and 99, respectively, of Fig. 6;

Figs. 10 and 11 are sectional views taken on the lines Hl-l0 and H-| I, respectively, of Fig. 3;

Fig. 12 is a fragmentary sectional plan view taken on the line l2-|2 of Fig. 6; and

Fig. 13 is a small-scale elevational view showing the burner mounted to fire a boiler.

Referring to these drawings, and first to Figs. 1 and 2 thereof, the burner includes a suitable fan, the housing of which is marked l6, for supplying air to the burner; a suitable pump 11 for supplying oil to the burner; a motor 18 for driving both fan and pump; and a cylindrical air tube I 9 through which air is conducted to the point of combustion. Within this tube (Fig. 6) is a suitable nozzle 20 for emitting oil in finelydivided formto be mixed with the air. The nozzle, in this particular case, is of the pressure atomizing type. The air tube may have any suitable outlet nozzle or other means for directing the air to the oil spray, such for example as the nozzle 22 (Figs. 1 and 2). The assembly described is usually supported (see Fig. 2) by several legs, such as 2|, and the forward end of the air tube I9 is inserted through a wall to of the heating unit so as to communicate with the combustion chamber 0 thereof in the usual or A further object of the invention is to provide 55, any suitable manner.

The elements, above described, are found in the association described in many burners of the prior art. The burner described thus merely constitutes the setting or background for the present invention, which relates primarily to apparatus for preheating the oil and bringing it up to a predetermined temperature before flow of the oil to the atomizer nozzle is permitted.

In carrying out the invention, an adapter ring 23 (Fig. 2) is interposed between the outlet end of fan housing l6 and the inlet end of air tube l9, and is suitably secured to the housing asby cap screws 24. The tube H) is also suitably fixed to the adapter as by screws 26, which clamp the end of the tube against a circular flange (Fig. 6) on the adapter. This adapter'supports on its upper side a manifold 21 which is fixed by cap screws 28 (Fig. 3) to the adapter-and which is provided with various chambers and passages for the oil. The manifold, in turn, is connected as shown in Fig. 6 to.supply oil to the nozzle 26 and to circulate oil through jackets which encompass the oil supply passage, all as willbe more particularly described hereinafter.

The manifold 21 will first bedescribed. Referring to Figs. 1 and 3,.this manifold is provided at a point intermediate its ends with a verticallydisposed, cylindrical chamber 30 and on opposite sides of this chamber with chambers 3! and 32. The chambers 3| and 32 are inlet and outlet chambers, respectively, for the low-pressure oil used for heating the oil-supply passage of nozzle 26. The chamber 30 is for the high-pressure oil used to supply said passage and nozzle. Adjacent the inlet chamber 3| at one end of the manifold is a cylindrical chamber 33 fora pressureregulating and by-pass valve. Partially surrounding the chamber 33 is an inletjacket composed of two connecting portions 34 and 35 (Fig. 11). The pump I"! has a discharge pipe 36 (Fig. 1) and this pipe is connected to the portion 34 (Figs. 10 and 11) The portion 35 is connected by a port 3'! (Figs. 3 and 11) to chamber 33 near the base thereof. An L-shaped outlet passage 38 (Fig. 10) is provided forthehigh-pressure oil which passes the pressure-regulating valve to be described. This passage 38 extends horizontally rearward below the chamber 33 and thence upwardly toward the portion 34 of the inlet jacket, such portion being of less height than the portion 35 in order to accommodate the upwardly extending part of passage 38. At its'upper end passage 38 communicates with one end of a'passage 39 (Figs. 5 and 10) which extends in back of inlet chamber 3| (Fig; 5) and at its other end is connected by a port 40 with the chamber 36. The upper end of valve chamber 33 is connected by a port 4| (Fig. 3) to an arcuate recess 42 which forms an upward extension of inlet chamber 3| near one end thereof.

The oil supply connections between the. manifold 21 and the nozzle '26, together with the'connections between the manifold and'theheating jackets will next be described. Below and axially-aligned with chamber 30 and separated therefrom by a wall 43 (Figs. 3 and '6) 'is a cylindrical recess 44. A casting 45 having a'fiange 46 secured "by cap screws to the lower wall of the manifold, has a cylindrical portion'48 which close- 'coaxially of and encompasses pipe 64.

bers 3| and 32, respectively. The central passage 50 is connected at its upper end to a short pipe 56 having on its upper end a seat for a valve 51. The pipe 56 extends through wall 43 and is screwthreaded into the upper end of the cylindrical part 48 of casting 45. As shown in Fig. 6, the casting 45 is fixed, as by cap screws 58, to a casting 59. The casting 59 has three passa es 66, 6| and 62 (Fig. 8), which respectively communicate as shown in Fig. 9, with passages 49, 56, and 5|'. These passages 60, 6|, and 62 have their lower terminal ends disposed in a common horizontal plane (Fig. 12) which passes through the axis of the cylindrical lower end 63 of casting 58.

The end 63 is bored out to receive one end of a pipe 64 and is counterbored to receive the corresponding end of a larger pipe 65 which is disposed The left hand end of pipe 64 extends beyond the corresponding end of pipe 65 and communicates with the p age 6|. The passages and 62 open into the end face of the counterbore which receives pipe and they communicate with the latter at diametrically opposite points. The annular space between the pipes 64 and 65 is partitioned by two members 66 (Fig. 7) which are suitably fixed to the outer wall of pipe 64, as by welding, and which extend longitudinally of the pipe, one along the top and one along the bottom thereof. These members divide the aforesaid annular space into two parts or jackets 61 and 68, with which the passages 66 and 62, respectively, communicate. The members 66 (Figs.

12 and 6) extend from the left hand end of pipe passage, as 61, and through such passage, to enter into the right hand end of the other passage,

as 66, and return to the left hand end of such passage. The left hand end of pipe 64 has a press fit in its recess in the end 63 of casting 58. The left hand end of pipe 65 closely fits 1n the counterbore in such end 63 and the pipe 65 is fixed to end 63 in any suitable way, as by welding.

The structure described provides an oil feed passage which extends from chamber 36 to the nozzle 20 without interruption. This feed passage may be traced as follows: from chamber 36 through pipe 56, passages 56 and 6|, pipe 64 and passage 16 to nozzle 26. The structure also provides a continuous heating passage from the chamber 3| of the manifold 21 extending alongside'the feed passage to a point near the nozzle end thereof and then returning along the opposite side of the feed passage to the chamber 32 of the manifold. This heating passage may be traced as follows: from chamber 3| through passage 54, port 52, passages 49 and 66, jacket 61, spaces jacket 68, passages 62 and 5|, port '53 and passage 55 to chamber 32.

The pressure-regulating and by-pass valve will next be described with reference to Fig. 3. Threaded into the bottom wall of chamber 33 and upstanding therefrom is a hollow barrel 12 which communicates at its lower end with the outlet passage 38 for high-pressure oil. The barrel is counterbored to slidably receive a plunger 13, havingdepending therefrom a valve 14 to control communication between the interior of the barrel and outlet passage 38. Ports I in the side wall of barrel '2 above the seat for valve 14, enable oil from chamber 33 to enter the hollow interior of the barrel at a location below the plunger 13-. A spring 16 tends to raise this plunger and open valve 14. The plunger, however, has fixed thereto a second valve 11 which projects upwardly through the top end of the barrel and engages the lower face of a piston 18,- closing an opening 19 which extends through the bottom wall of the piston. The piston is slidably mounted in the upper part of chamber 33 and is forced downwardly by a spring 38, mounted between the piston and a suitable seat provided within a cap 8| which is threaded into and closes the otherwise open upper end of chamber 33. The tension of this spring is adjustable in the usual or any suitable manner. The spring 88 is 'much stronger than spring 16 andthus holds valve 14 closed until a pressure has been built up in chamber 33 beneath the piston of sufficient degree to raise the latter, say for example 150 pounds per square inch. When the piston 18 commences to rise, valves 14 and 11 and plunger 13 will rise with it because of the lifting effect of spring I6. Valve 74 will thus open and allow oil to fiow from chamber 33 to passage 38. The valve 11 does not, however, immediately open. When the plunger 13 rises far enough to engage the upper wall of barrel 12, the upward movement of both valves will be stopped. Thereafter, as the piston continues to rise, it will draw away from the valve 11, opening the passage 19. Then oil from the lower part of chamber 33 will pass through the piston into the upper part of the chamber and thence pass through port 4| and recess 42 into inlet chamber 3|. This oil which is bypassed and at low unit pressure is used for heating purposes in the circulatory heating passages above described.

Provision is made, whereby the pressure of that body of oil contained in passages 38 and 39, port 48 and chamber 33 will be automatically reduced to that existing in chamber 33, whenever valve 14 is closed. An axial passage 82 (Fig. 3) in this valve extends upwardly from its lower end and communicates by means of side ports 83 with the interior of barrel I2 and thus with chamber 33.

A check valve 83', preferably spring-pressed as shown, is provided in the passage 82 between the ends thereof. This valve opens whenever the pressure on the lower side of the valve exceeds that in chamber 33, allowing back flow of oil into this chamber until the pressures on opposite sides of valve 14 are equalized. The spring associated with valve 83' does not exert any substantial pressure on the valve and is there merely to insure that the valve is held to its seat more positively than it would be if gravity alone were relied on for the purpose. Because of the provision described, whenever the oil pump stops, the pressure in chamber 38 and in the port and passages communicating therewith is automatically reduced usually to zero and in any case to whatever pressure exists in chamber 33.

A pressure gauge 84 may be connected to the inlet passage as shown.

The chamber 32 has two outlets. One outlet is by way of a pipe 85 (see Fig. 4) which pipe extends, as shown in Figs. 1 and 2, to the inlet end of a suitable oil heater, such as the electric heater indicated at 86. A spring-loaded check valve 81 is interposed in pipe 85. This valve opens to permit flow toward and into the heater 86 when a small pressure, say from to 10 pounds per square inch;*has been built up in the chambers 31 and 32 and the oil circulation passages connected therewith.

The heater 86 has its own thermostatic switch, designated. 88, for controlling the supply of current thereto and it may also be additionally controlled by other means not herein shown.

The heater hasan oil inlet 89 adjacent pipe (see Fig. 2). The outlet end of heater 8600mmunicates with a filter of any suitable form within a casing 98, preferably formed as a part of the casing of the heater, whereby the oil within the filteris kept warm. Oil from the filter passes by way of a pipe 9| to the suction side of pump I'I. Thus, the pump may draw oil from either pipe 85 or the inlet 89, sucking it through the heater and filter and then forcing it into the chamber 33 of the pressure-regulating and bypass valve.- Until valve 57 opens, the only outlet for the oil is into chamber 3|, and thence through the circulation passages associated with the nozzle supply passage and thence back .to chamber 32. Initially, oil leaves this chamber only by way of pipe 85 and then passes back to the inlet side of the oil heater. Therefore, a relatively small volume of oil only is necessary for the circulation through the heater and along the nozzle supply passages for heating purposes. A quick raising of the oil temperature can thus be secured.

The temperature of the oil may be indicated on a suitable thermometer 92 communicating with chamber 32.

The other outlet for chamber 32 is by way of a pipe 93 (Fig. 3) which is adapted, as shown in Fig. 13, to return oil to the oil supply tank I28. Communication between the chamber 32 and return pipe 93 is controlled by a valve which opens in response to rise in temperature of the oil in the chamber, opening the valve only when such temperature reaches a predetermined degree. Initially then, this Valve is closed. As herein shown, a hollow barrel 94 is fixed to and upstands from the lower wall of chamber 32. The lower end of this barrel is in constant communication with pipe 93. The barrel has side ports 95 enabling communication between the interior of the barrel and chamber 32. A sleeve valve 96 slides in this barrel and has ports 91 adapted to register with ports 95 when the oil temperature reaches the predetermined degree. A spring 98 tends to raise the valve and keep ports 95 closed. Fixed by a capscrew 99 to a cap I98 threaded into the top wall of chamber 32 is a thermostatic bellows llil, to the lower end of which the flange 96' of the valve 96 is fixed. As the temperature of the oil in chamber 32 rises, the bellows l8l extends and forces the valve 96 downwardly, causing ports 95 and 91 to communicate when the desired oil temperature is attained and thus allowing oil to flow back to the supply tank. Any suitable provisions may be made for adjusting the temperature at which valve 96 will open. As shown herein, the spring 98 is interposed between the upper end of the barrel and the lowermost of two washers 98 on the stem of the valve below flange 96. By varying the number or the thickness of these washers or by both, the pressure which opposes the bellows iOI and thus the temperature at which valve 96 will open can be varied as desired. Any other suitable means for controlling valve 96 in response to oil temperature may be used, as desired.

Thevalve 1, whichcontrols the flow of highpressure oil :from chamber 30 tothe nozzle 20,.is automatically opened when the oil has attained the desired predetermined temperature. example, the valve-may be operated electromagnetically under the control of a thermostat switch designated I03, having a thermal element I04 extending into chamber 32 (Figs. 4 and 5). This switch is arranged to close when the oil in chamber 32 reaches the desired predetermined temperature and theclosing of the switch is arranged to energize a solenoid I05 which raises valve 51. The solenoid is mounted on a body I06having a flange I91, which is secured by cap screws I08 to the top of manifold 21. Preferably, a baflie, such as I04 (Fig. 5) is provided in order to deflect the oil which enters chamber 32 through port 55 toward the thermostat element The high-pressure oil chamber 30 is preferably provided with a screen I09 which is heldbetween the flange I01 and the bottom wall of chamber 30, the ends of the screen fitting into recesses, one in said flange and one in said wall.

The various pipe-plugs, such as IIO, shown in the manifold 21, are used to plug the holes, left by the supports for the cores, used during the casting of the manifold.

Referring to Fig. 13, the burner is shownas used for firing any suitable heating unit, say for example a boiler III. This boiler has an indirect heater II2 through which water from the boiler circulates by means of pipes H3 and H4. The water is arranged to heat the oil which enters the heater by a pipe II5, leading from the oil supply tank I28 and leaves by a pipe II6, which extends to the above described inlet 89 of the electric heater 8B. The pipe I I5 may have a foot valve I29 thereon.

In accordance with usual practice, the air tube I9 (Figs. 1 and 2) has an opening in the upper portion thereof, and such opening is normally closed by a cover II1 held in place by screws II 8. By removing this cover and the plate, one may remove the oil supply and heating conductors together with the nozzle and the usual nozzle support, such as II9 (Fig. 6), and the ignition electrodes, such as I20, which are supported by insulators I2I from the member H9. The cap screw 9' which holds support H9 in place in tube I9, is first'removed. Then by removing the cap screws 58, one may separate the two castings 45 and 59, whereupon after the casting 59 has been turned enough to clear casting 45, the casting 59 and the attached pipes 84 and 55 and nozzle may be drawn rearwardly and lifted upwardly through the opening in the air tube.

The casting 45 extends through a slot I24 (Fig. 6) in the adapter ring 23. This slot is open at one end. To prevent air from passing outward- 1y through this slot, a plate I is laid on the top wallof the adapter 23 to overlie the open portion of slot I24 and to fit closely against the front and sides of that portion of the casting which lies in the slot. This plate is fixed to the adapter by screws I26. This plate may have an upturned flange I21 to abut the cover H1 and exclude outflow'of air from the tube I9 above plate I25.

The burner structure described maybe provided with any suitable electrical controls, which may be contained for the most part in a control box I22. One example of a control system suitable for this burner is disclosed in our copendingapplication' Serial No. 314,102, filed January 16, 1940.

The operation of the burner will next be described. The burner will be started up automatically, on a demand for heat, by suitable controls such for example as those disclosed in the above identified application, which controls set in operation the motor I8, fan I6 and pump I1 and usually also turn on the electric heater 8B and the ignition means. Flow of oil to the nozzle is, however, prevented by valve 51 unless and until the oil has been heated to the desired predetermined temperature. This temperature may, for example, be assumed to be from to Fahr. for N0. 5 fuel oil. Assuming that the oil temperature is low, the thermostat valve 95 will be closed with the result that the oil will be forced by pump I1 to circulate through the short path described. The pump will put the oil under a small pressure, sufficient to open the spring-loaded check valve 81. Oil will be forced into the manifold 21, out through jacket 61 to a position closely adjacent nozzle 20, back through jacket 63 to the manifold, and thence by way of pipe 85 through valve 81' into the inlet side of the electric heater 86, from which oil is delivered to the suction side of the pump. It is to be noted that no oil will pass through the indirect heater H2 and this is a most important feature. The normal function of heater H2 is to yield heat to the oil which passes therethrough by a heat exchange betweenthe water in the boiler III and the oil. But, if this water is cold and the oil which has been heated by heater 8B is allowed to pass through heater 2, the oil will be cooled. The normal heat exchange will be reversed and the oil will yield its heat to the Water in the boiler and unless and until the water is brought up to the desired oil temperature, the burner cannot operate. Thus, the initial use of the indirect heater would delay the starting up of the burner.

The quickest Way to heat the water in boiler HI is by direct firing of it by the oil burner. This occurs as soon as the oil has been heated to the proper degree, because the thermostat switch will close and cause energization of solenoid I05, thereby raising valve 51 and allowing heated oil to now through the passages, which form the nozzle feed pipe, into nozzle 29. At or about the same'time, but preferably somewhat later, the thermostat IilI will open valve 96 and allow circulation of oil through the long circuit which includes the'supply tank and the indirect heater H2. The thermostat I0! is usually set to open valve 96 only after the oil has risen to a temperature somewhat abovesay 5 to 10 degreesthat at which valve 51 opens.

In starting up the burner from a cold condition with the Water in the boiler also cold, the burner 'may not at first continue in operation very long after it has beenstarted. After the nozzle valve 51 has opened and oil is supplied to and ignited at the nozzle, the water in the boiler begins to warm up. Obviously, the oil consumed at the nozzlemust be drawn from tank I28 through the indirect heater II2. Consequently, the oil temperature in the manifold will be lowered and eventuallyilowered to a point where the valve 51 will close and stop flow of oil to the nozzle. The fire goes out but the pump continues in operation, forcing oil in the short path through the electric heater, whereby the oil will soon be heated to the point'where valve 51 will again open and allow'oil to be fed to and-ignited "the pumped oil attains a predetermined pressure, the second valve opening only when-the oil atat the nozzle, thereby again firing the boiler. Usually, the burner will run four or five minutes on the first start and then stop. Two or three starts usually sufiice to secure operation which is continuous. Thereafter, the temperature of the oil in the manifold will rise to a point where valve 96 will open, whereupon oil will then circulate through the longer circuit which includes the tank I28 and the indirect heater I I2.

When the boiler-water is not cold (and it is usual to maintain it by thermostatic control at same predetermined temperature above that at which valve 51 opens), then the repeated starting and stopping of the burner, above described, will not usually occur.

The provision of the manifold 21, in which are mounted all of the various valves 51, I4, 11 and 96, thermostats l! and I04, the pressure gauge 84, and thermometer 92, is an important feature of the invention. Notonly are all these necessary instruments grouped together in one place and made conveniently accessible but they are kept warm by the body of hot oil contained in the chambers of the manifold and thus in condition to be instantly responsive in the performance of their intend-ed functions. The manifold together with the adapter ring 23 enables a standard burner to be easily converted into one having the oil-preheating provisions. The adapter ring '23 which carries the manifold, is simply interposed between the outlet of the fan housing It and the inlet end of the air tube I9 and all that remains to do is to connect three pipes 36, 85 and 93 thereto.

The temperature-controlled valve 51 is purposely located away from the nozzle 20 to keep it away from the intense heat which might interfere with its proper functioning'and also to make it accessible. With the remote location of this valve, the provision of the jackets Gland 58 and their connecting passages enable the warming up of that body of oil which is trapped between the valve 51 and the nozzle 20. The oil feed conduit has uninterrupted heating passages extending between such valve and nozzle so that, when flow of oil to the nozzle eventually occurs, there will be no possibility of the emission of any slug of cold oil. All the oil will be brought up to temperature by the circulatory heating system described. Even the oil contained in the nozzle 20 and in passage 10 will be heated by conduction from the pipes 64 and 65.

The invention thus provides an improved means for preheating the fuel in an oil burner,

which insures that the oil may be quickly raised to the desired temperature and maintained within close limits at such temperature. No.oil can pass to the nozzle until it has attained the selected temperature. Unless the oil is at the right temperature and also under the proper pressure, it cannot pass to the nozzle.

What we claim is:

1. In an oil burner, having an oil pump, an oil-atnmizing nozzle, and a feed pipe for supplying oil thereto, said pipe having heating jackets extending from end to end thereof and disposed one on each side thereof, said jackets being interconnected near the nozzle end thereof, an oil heating means, a supply pipe leading to the inlet end of said means, a pipe connecting the outlet end of said means to the inlet end of said pump, a conduit connecting the outlet end of saidpump to said feed pipe, first and second valves interposed in series relation in the order named in the last-named conduit, the first valve opening when tains. a predetermined temperature, a by-pass for diverting excess oil supplied to the first valve, a conduit connecting said by-pass to the inlet end of one of said jackets, and a conduit connecting the outlet end of the other of said jackets to the inlet end of said heating means.

2. In an oil burner, having an oil pump, an oilatomizing nozzle, and a feed pipe for supplying oil thereto, said pipe having heating jackets extending from end to end thereof and disposed one on each side thereof, said jackets being interconnected near the nozzle end thereof, an oil heating means, a supply pipe leading to the inlet end of said means, a pipe connecting the outlet end of said means to the inlet end of said pump, a conduit connecting the outlet end of said pump to said feed pipe, first and second valves interposed in series relation in the order named in the last-named conduit, the first valve opening only when the pumped oil attains a predetermined pressure, the second valve opening only when the oil attains a predetermined temperature, a by-pass for diverting excess oil supplied to the first valve, a conduit connecting said by-pass to the inlet end of one of said jackets, a conduit connecting the outlet end of the other of said jackets to the inlet end of said heating means, and a check valve controlled by-pass for enabling back flow around the first valve to equalize the pressure on opposite sides of said valve.

3. In an oil burner, wherein air for combustion is supplied by'a fan through a tube and oil is supplied through a feed pipe located within said tube to an oil-atomizing' nozzle, a manifold mounted on said tube adjacent the fan and having therein a chamber for oil to be fed to said pipe and nozzle and also having therein inlet and outlet chambers, a pressure-regulating and bypass valve mounted in said manifold and having its inlet connected to said pump and its high pressure outlet connected to the first-named chamber and its by-pass outlet connected to said inlet chamber, the first-named chamber having an outlet connected to said feed pipe, a valve controlling said outlet, said feed pipe having heating jackets the inlet end of one of which is connected to said inlet chamber and theoutlet end of the'other of which is connected to said outlet chamber, the outlet end of the first J'a'cket being connectedat a point closely adjacent the nozzlev to'the inlet end of the second jacket, a

heating means for oil, a connection between said outlet chamber and the inlet of said heating means, a connection between the outlet of said heating means and said pump, and a thermostat located in said outlet chamber and operable to open said valve when the oil in said chamber attains a predetermined temperature and to close said valve when such oil is below said temperature. r

4. In an oil burner, an oil-atomizing nozzle, means for heating the oil to be supplied to said nozzle, a conduit extending from the heating means to said nozzle, a valve in said conduit located a substantial distance from the nozzle and opening only when said oil has attained a predetermined temperature, a heating jacket for said conduit extending without interruption from said valve to said nozzle, and means for circulating oil heated by the first named means through said jacket to warm the body of oil trapped between said valve and nozzle. i

5. Fuel heating'means for an oil burner used for firing heating apparatus and having, a: first oil-heating means; dependent for effectiveness on operation of the heating apparatus, j a" second oil-heating means effective independently of the operation-of said apparatusand burner, a pump, and conduit means interconnecting' said pump and the first and' second oil-heating means in series relation and providing a relatively-long closed-loop path in which oilmay be circulated by said pump; conduit means cooperating with part of the first-named conduit means to provide a relatively-short closed-loop path'for the circulation of oil by said pump and including in series relation saidpump and the second only of said heating means; andmeans responsive to the temperature of the oil for causing the pumped oil to flow through'said short path and-be excluded from the long path until the oil has been heatedto a predetermined temperature by said second heating: means and forthen causing the located in heat exchange relation with said supplypipe, a pump, and conduit means interconnecting said pump and heating conduit'and the first'and second oil-heating means in series relation and providing a relatively-long closed-loop path in which oil may be circulated: by said pump; a valve insaid'conduit means located between the outlet of said heatingconduit and'the inlet of the first heating means, means responsive to' the temperature of the oil for opening'said valve only when the oil iszat' or above a predetermined temperature and closing said valve when the oil is below. said temperature, a by-p'ass extending between two points in said conduit means, one of said points located'between the outlet of the first heating meansand the inlet -of the second heatingmeans andthe other of said points located'between said valve and the outlet end of the heating conduit, a check valve in said by-p'ass opening whenfsaid first valve is closed and when thepumped' oilexceeds a predetermined pressure to enable direct flow from the heating conduit to the secondTheating means to the exclusionof the first heatingmeans.

7. Fuel heating means for an oil burner used for firing heating apparatus andhaving, a' first oil'eheating means dependent for effectiveness on operation of the heating apparatus, a-second'oilheating means efiective independently of .the op- .erationofsaid apparatus and burner, an oil'supplypipe for said burner, a heating'conduit located: in heatexch'ange relation withsaid pipe, a pump, an oil supply tank; an oil conduit connectingi'jsai'd tank t'otheinletiof-isaid heating conduit andhavingtinterposedtherein in series relation and in the order named said first heating means, said. second heating means, and said pump; afirst'return conduit'connecting the Loutlet ofsaidlheatin'g conduit to the inlet of the second'heatingmeans, a check valve in saidreturn conduit, 9; second return conduit extending from the outlet of said heating conduit to said-tank, afvalve for closing thesecond return conduit, whereby the oil circulated'by the pumpwill pass through the second only of said heating means,

and meansresponsive to'the temperature of the 5 oil in said heating conduit for opening said lastnamed valve when such oil has been heated to a predetermined temperature, whereby the oil circulated by the pump will then pass through both heating means and said tank.

8. Fuel heating means for an oil burner used for firing heating apparatus and having, a first oil-heating means dependent for efiectiveness on operation of the heating apparatus, a second oilheating means efiective independently of the operation of said apparatus and burner, an oil supply tank, a pump, a suction conduit connecting thetank and pump and having interposed therein the first and second heating means, a discharge pipe for said pump, a pressure regulating valve and a by-pass valve, each said valve having its inlet connected to said discharge pipe, a feed pipe'connected at one end to the outlet of the pressure regulating valve and an atomizing nozzle on the other end of the .feed pipe; a heating conduit mounted in heat exchanging relation with said feed pipe and having its inlet connected to the outlet of said'by-pass valve, a third valve located in said feed pipe between the nozzle and the pressure regulating valve, means for opening the third valve only when the oil has been heated up to a predetermined temperature, a first return conduit connecting the outlet of the heating conduit to the inlet of said second heating means, a check valve in said return conduit, a second return conduit connecting the outlet of the heating conduit to said tank; a' valve for initially closing the second return conduit, wherebythe pump will circulate oil through the heating conduit and the second heating means only; and means responsive to the temperature'of the oil in said heating conduit for opening the last-named valve, when such oil has been heated to a'predetermined temperature, whereby the pump then circulates oil through the heating conduit and both heating means and said tank.

9. In an oil burner, having 'a' pump, an atomizing nozzle and an oil feed conduit interconnecting the outlet of the pump and said nozzle, means for heating the oil supplied tosaid pump, two valves interposed in said conduit at a substantial distance from said nozzle, one of said valves opening only when the pumped oil attains a predetermined pressure, the other of' said valves opening only when the oil attains a predetermined temperature, a heating conduit mounted in heat exchange relation with that portion of the feed conduit located between said nozzle and'the nearest one of said valves, a conduit connecting said 'feed conduit at a point between the pump and'the valve nearest thereto to'the inlet of said heating conduit, a conduit connecting the outlet of the heating conduit to the inlet of theoil heating means, and a conduit connecting the outlet of the oil heating means to the inlet of said pump.

10. In an oil burner, having a pump, an atomizing nozzle and an oil feed conduit interconnecting the outlet of the pump and said nozzle, means for heating theoil supplied to said pump, a valve responsive to pressure of the pumped oil and a valve responsive to the temperature of' the oil, said valves interposed in the feed conduit in series relation with the first-named valve nearest to the pump and the second-named valve nearest to'the nozzle but both valves being spaced a substantial distance from the nozzle, both valves being initially closed to prevent flow of oil to the nozzle, a heating conduit mounted in heat exchange relation with that portion of the feed conduit which lies between the'temperature responsive to pressure of the pumped oil, the inlet of said heating means being connected to the outlet of the heating conduit and the outlet of said heating means being connected to the inlet of said pump.

HARRY F. TAPP. LEOLYN F. SPEAB. 

